As used in different countries, the concept "non-alcoholic beer" refers to different kinds of products. In Spain, a product having an alcohol content of less than 1 is regarded as non-alcoholic while in Holland the limit is 0.5%. In the Arab countries, the alcohol content of non-alcoholic beer must not exceed about 0.05 by volume. In the U.S. and some other countries, a beverage having an alcohol content of less than 0.5% can not be called beer.
It is known from the prior art to produce nonalcoholic beer by batch-type processes, which, however, are difficult to carry out (see e.g. U.S. Pat. Nos. 4,746,518 and 4,661,355). Wort is treated at a low temperature of about 0.degree. C. to prevent the formation of alcohol.
In batch-type processes, it has proved difficult to keep the process parameters, such as the delay, the temperature, and the concentration of dissolved oxygen, precisely at the desired values (at equilibrium). Even a minor deviation from the desired values may result in the formation of alcohol, so that the alcohol content of the product obtained is in excess of the value allowed in, for instance, the Arab countries, that is, 0.05% by volume.
Furthermore, a process is known from the prior art for the production of non-alcoholic drinks at a relatively low temperature, 2 to 15.degree. C. (EP 0 213 220). In the process, aerated wort is passed rapidly through a reactor containing immobilized yeast. This process, however, is not particularly suitable for continuous production because the reactor clogs in a very short time.